Specimen holding device with means to tilt, rotate and shift the specimen



March 15, 1966 MASARU T BE ETAL 3,240,934

SPECIMEN HOLDING DEVICE WITH MEANS TO TILT, ROTATE AND SHIFT THESPECIMEN Filed Feb. 13, 1963 2 Sheets-Sheet 1 l5 FIG.2 89 3 6&

la A 4 March 15, 1966 MASARU WATANABE ET AL 3,240,934

SPECIMEN HOLDING DEVICE WITH MEANS TO TILT, ROTATE AND SHIFT THESPECIMEN Filed Feb. 13, 1963 2 Sheets-Sheet 2 United States Patent3,240,934 SPECIMEN HOLDING DEVICE WITH MEANS T0 TILT, ROTATE AND SHIFTTHE SPECIMEN Masai-u Watanabe, Shigeru Suzuki, and Yoriaki Nagahama,Tokyo, Japan, assignors to Nihon Denshi Kabushiki Kaisha, Tokyo, JapanFiled Feb. 13, 1963, Ser. No. 258,339 Claims priority, applicatgongapan, Feb. 14, 1962,

,45 3 Claims. (Cl. 250-495) This invention relates to a specimen holdingdevice for use in electron beam apparatus such as electron microscopes,electron ditfraction cameras, etc.

In the use of electron beam devices such as electron microscopes, it isbecoming more and more important to be able to tilt the specimens. Thisis brought about by the fact that in the study of crystalline structuresor in the examination of individual crystals, it is necessary to be ableto examine such crystal at any optional position of the specimen alongany crystal axis. It is not possible to make precise observations of acrystalline specimen if the angle of the specimen to the incidentelectron beam is effected by chance. Conventional electron microscopespecimen holding devices frequently incorporate specimen tilting means,however, with such means it is possible to tilt the specimen only withrespect to the optical axis and there is no choice of the azimuthalangle of the specimen in respect to the optical axis because no meansare provided to rotate and/ or shift such specimen. Consequently, once aspecimen is set in the conventional tiltable specimen holder, only thatportion of the specimen which happens to coincide with the tilting axiscan be tilted without drift. The other parts of the specimen which donot coincide with the tilting axis will escape from the visual fieldwhen the holding device is tilted since they will be tilted out of theaxis. Accordingly, the conventional specimen holding devices are notsuitable for continual observation of a specimen.

Other devices and methods heretofore employed to position specimens ontiltable holding devices While maintaining the visual field on apredetermined part of a specimen are complicated and it is exceedinglydiflicult by employing these means to vary the tilting angle of thespecimen continually and gradually. Consequently, the prior art tiltablespecimen holders and aforesaid devices for maintaining the visual fieldof a predetermined part of a specimen while tilting the specimen are notsuitable for the observation of crystalline specimens.

By means of the apparatus of the present invention, it is possible totilt, rotate or shift a specimen (substantially horizontally) withrespect to the electron beam so that continual observation of any partof the specimen for any desired angle may be satisfactorily made.

The present invention is a tiltable specimen holding device that isprovided with means for etfecting independent rotation of the specimenand additionally means for efiecting independent shifting of thespecimen, such combination of means making it possible to rotate andshift the specimen in a substantially horizontal plane at any optionallyselected tilting angle without being confined to that part of thespecimen that happens to fall under the electron beam when such specimenis inclined. By means of the apparatus of the present invention, it ispossible to align the tilting axis and the rotational axis of that partof the specimen to be observed with the optical axis of the microscope.The specimen can then be optionally tilted and/ or rotated for continualobservation of any optionally selected part of the sample. In otherwords, the apparatus of the present invention permits a device such asan electron 3,240,934 Patented Mar. 15, 1966 microscope to effect amicroscopic image or an electron diffraction pattern of an optionallyselected portion of a specimen as tilted or rotated to any desired anglewith respect to the electron beam.

Such advantages are possible because of the unique mechanical structureof the present apparatus which consists of a stage, a tiltable cartridgesupported by the stage, a circular rotary mount fixed on the tiltablecartridge in a manner to permit free rotation, a mobile specimencartridge inserted into the rotary mount and gears arranged adjacent tothe rotary mount that effect shifting position control of the mobilespecimen cartridge. In the present apparatus the specimen cartridge isseated on the rotary mount in a manner to permit horizontal adjusment.

By means of the apparatus in the present invention, a tilting axis ofthe specimen containing cartridge may be adjusted to cross the opticalaxis (electron beam) by means of the specimen shifting mechanism andthen the specimen which is seated in the specimen cartridge may berotated by means of the rotary mount without disturbing the abovementioned axis configuration. Accordingly, the axis of the crystallinespecimen may be adjusted in the specimen plane so that it is parallel tothe tilting axis, additionally, the specimen cartridge can be shifted sothat any optionally selected crystal axis may be made to coincide withthe tilting axis. It will be appreciated that where an optionallyselected crystal axis completely coincides with the tilting axis, theimage may be observed from any angle of incidence of the electron beamby effecting any degree of tilting of the holder without being subjectedto specimen drift. The rotative shifting and tilting adjusments may bemade independently of one another so that any position from anyazimuthal angle of the specimen may be readily examined.

Another feature of this invention is that the tiltable specimen holderpermits the specimen to be inserted deeply in the electron microscope ornear the center of the objective lens pole piece which enables one toobtain a high resolution. Hence, the specimen holding device of thepresent invention may be said to provide improved means for observingtilted specimens and, additionally, effects an apparatus that enablesthe obtaining of high resolution.

Other advantageous features of the present invention will be obviousfrom the following description and the drawings wherein:

FIGURE 1 is a plan view of an electron microscope specimen holdingdevice that embodies features of the present invention;

FIGURE 2 is a cross-sectional view of the apparatus in FIGURE 1 as seenfrom along the line IIII thereof; and

FIGURE 3 is a perspective view of the apparatus of FIGURES l and 2.

In the apparatus of FIGURE 1 and as illustrated in FIGURES 1 through 3,a stage 1 is shown to be fixed to a conventional specimen shifting mount3. Mount 3 is the type of a mounting conventionally employed inconjunction with the ordinary transmission type electron microscope. Acollar and hold down bolts 2 are associated with the conventional meansand will not be described in detail in the present specification.

Two downwardly depending legs of the Stags 1 identified in FIGURE 2 as1a and 1b project into the interior of the objective lens pole piece 4.At the lower edge of the legs 1a and 1b, holes are provided to receivepins 4 which form tilting axle 5a and 5b of an elongated hollow tiltablecartridge 6. The tiltable cartridge 6 is provided with a rim 6a such asshown in FIGURE 2. The tiltable cartridge 6 is also provided with pillowblocks 7a and 7b upon which the pins are pivotally mounted to form thetilting axle 5a and 5b. The axle 5a and 5b is aligned on a plane whichcoincides with the tilting axis RR so that the specimen which is mountedin the lower portion of the holder for the specimen, the specimenholding cartridge 11 may be tilted with respect to the optical axis AA.The exact means in which the tilting mechanism functions will bedescribed in fuller detail herebelow.

On the rim 6a of the tiltable cartridge 6, there is positioned arotatable mount or first mounting plate 8. The rotatable mount 8 isloop-shaped and is disposed to be rotated freely on the rim 6a of thetiltable cartridge 6. The central axis of the rotatable mount 8 may beadjusted to intersect the optical axis AA and the tilting axis RR of thespecimen surface (see FIGURE 2) and the specimen is preferably seated atthe junction or cross-point of these three axes.

A helical Worm drive 9 is appropriately mounted to the rim 6a of thetiltable cartridge 6. Worm drive 9 meshes with gears formed in theperiphery of the rotatable mount 8. The axle 9a of worm gear 9 is driventhrough a universal joint (not shown) by a shaft projecting externallyof the electron microscope. Hence, worm gear 9 may be caused to rotateto transmit rotative movement to the rotary mount 8 by manipulating auniversal joint from outside of the electron microscope and as will beshown herebelow, such rotative motion is transmitted to the specimenholding cartridge 11 to effect rotation of the specimen.

It is understood that the specimen holder of the present invention asshown by the embodiments of FIGURES 1 through 3 is conventionallymounted within the housing of an electron microscope and that suchhousing must be of sufiicient continuity to permit a vacuum to becreated in the vicinity of the specimen to allow observation of thespecimen through electron bombardment.

The worm drive 9 must be freely operable from the outside of the housingof the electron microscope without interfering with the vacuum within.

Positioned as seated within the central opening of the rotatable mountor second mounting plate 8 is a looprimmed horizontal shiftable mount10. The specimen cartridge 11 projects through the central opening ofthe shiftable mount 10 so as to be supported Within the rotatable mount8. The specimen cartridge may be removed and replaced by lifting it fromits seat within the shiftable mount 10. In effect, the specimencartridge 11 is inserted into the interior of the rotatable mount 8 andis merely supported within the surface of the rotatable mount 8 by theshiftable mount 10.

The horizontal shiftable mount 10 iits loosely within the centralopening of the rotatable mount 8 so that it is susceptible to horizontalpositioning within such mount.

The mount 10 is caused to shift in its position on rotatable mount 8 bymeans of an interlocking mechanism that includes the spring 12,. bolts13 and 14, gears '15 and 16, and pinions 17 and 18 all of which areconcentrically arranged around the rotatable mount 8. The shiftingmechanism is clearly illustrated in FIGURES 2 and -3. Pinions 17 and 18mesh with the crawl gears 15 and 16. Central openings within pinions 17and 18 are threaded so that the bolts 13 and 14 are threadably engagedwith the respective central openings of the pinions 17 and 18. Bolt 13is formed with a pointed edge that takes the shape of a knife blade andas shown in particular by FIGURE 1, such edge bears upon a specificallyhardened insert positioned within shiftable mount 10. The end of bolt 14is rounded or hemispherical in shape and bears upon a flat area formedon the shifting mount 10. A spring 12 is appropriately attached at oneend to the rotatable mount 8 and at the other end to shiftable mount 10.The spring 12 is maintained under tension so as to urge the shiftablemount 10 against the edge of bolt 13 and the rounded end of bolt 14. Theshiftable mount 10 is consequently controlled in its horizontal positionby the horizontal position of the bolts 13 and 14 within the pinions 17and 18. When pinions 17 and 18 are caused to rotate, the bolts 13 and 14will be advanced or retracted in accordance with the direction of theirrotation. In the present embodiment, the rotation of the pinions 17 and18 is effected by rotation or circular movement of the crawl gears 15and 16. Rotation of the gears 15 and 16 is eflected through gears 27 and28 which are appropriately connected to universal joints and shaftsprojecting outside the housing of the electron microscope so that gears27 and 28 are caused to rotate when shafts 25 and 26 are caused torotate by such exterior means (not shown).

As may be seen, particularly in FIGURES 2 and 3, bolts 13 and 14 projectthrough openings within appropriate mounting members that are rigidlyattached to the rotatable mount 8. L-shaped members 19 are rigidlyattached to the mounting members and projected into elongated groovesformed in bolts 13 and 14 to prevent the rotation of bolts 13 and 14along with the pinions 17 and 18 so that they will advance or retractwhenever the pinions 17 and 18 are caused to rotate, such mounting meansalso being positioned to prevent the pinions 17 and 18 from becomingdisengaged with the crawl gears 15 and 16.

The bolts 13 and 14 are orthogonally positioned as shown in FIGURE 1 andthe specimen shiftable mount 10 is pulled by the spring 12 diagonallytowards and against the tips of the bolts. Consequently, the specimencan be moved towards the center of rotative movement of the rotatablemount 8 by appropriate rotation of the axle 25 and the gear 27 so thatthe crawl gear 16 causes the pinion 18 to rotate in a manner to causebolt 14 to push the shiftable mount 10. Similar mechanical adjustment ofaxle 26, gear 28, crawl gear 15, pinion 17 and bolt 13 will urgeshifting mount 10 in another direction. Obviously, if it is required,the appropriate axles 25 or 26 may be rotated in a reverse directionwhich will cause bolts 14 and 13 to retreat from shiftable mount 10 sothat spring 12 will appropriately urge the mount 10 in the desireddirection.

As previously described, cartridge 6 is pivotally mounted to stage 1 bya means of pins projecting into receptacles of the legs 1a and 1b ofstage 1, such pins being mounted to pillow blocks 7a and 7b which inturn are mounted to the cartridge 6. Consequently, the specimencartridge 11 mounted within rotatable mount 8 in shiftable mount 10 maybe shifted in position in respect to the optical axis A-A, and may betilted along the axis RR.

A lever 21 is pivotally mounted about a fulcrum 24 that is attached tothe upper surface of stage 1. The lever 21 is attached at one end to therotatable mount 8 and is urged to push against the mount 8 so as to tiltmount 8 and consequently cartridge 6 by springs 22 and 23 which areappropriately mounted to stage 1 and attached to the lever 21. A bolt 20which. is connected to a universal joint disposed to the operatedexterior of the housing is threadably engaged with a nut 29 that isrigidly attached to stage 1 so that the bolt 20 bears on one end of thelever 21. By rotation of the bolt 20 in a manner to cause it to bearupon lever 21, the lever is caused to pivot about the fulcrum 24 so asto oppose the springs 22 and 23. Advancing the bolt 20 causes therotatable mount 8 and consequently cartridge 6 to be tilted about theaxis of axle 5a and 5b. If the bolt 20 is rotated in a reversedirection, obviously the lever 21 will be urged in a reverse directionby the springs 22 and 23 to cause cartridge 6 to tilt in the oppositedirection. Hence, rotation of bolt 20 forward or backward makes thelever 21 push or pull on the rotary mount 8 to tilt a specimen withincartridge 6 about the tilting axis RR.

As previously described, the apparatus of the present invention consistsof a stage that is rigidly attached to a conventional type shiftingmount 3. The shifting mount 3 is caused to adjust the position of theapparatus in respect to the optical axis (electron beam) by meanssimilar to the shifting means provided for such horizontal positionconsisting of the shifting mount 10. A spring similar to spring 12 urgesthe mount 3 in a direction diagonal to two elongated members which bearon the mount 3. The purpose of the shifting mount 3 is to adjust theapparatus prior to inserting the specimen. The apparatus of the presentinvention provides means for optionally rotating, tilting, and shiftingthe sample so that any desired view and angle may be observed after theinitial alignment has been accomplished.

The above described rotational, tilting, and shifting mechanisms arepositioned on stage 1 of the specimen shifting mount 3 and the tiltingaxis RR may be made to mechanically intercept the rotational axis. Byshifting the stage 1, the above described cross-point can be adjusted tomeet with the optical axis so that the tilting axis, rotational axis andoptical axis meet at one point.

As described above, the present apparatus is provided with the adjustingmechanisms 9, 12-18, 20, 21, etc. which consists of a variety of gearsmounted on or near the rotatable mount 8 (including the upper part ofthe tilt'able carriage 6) and through this adjusting mechanismhorizontal shitting, rotation and tilting of the specimen, including theadjustment of the three aforementioned axes, is accomplished.

In the operation of the present apparatus (omitting the routineoperational procedures employed in the use of an electron microscope)the cross-point of the rotational axis and the tilting axis are firstadjusted to meet with the optical axis (electron path) by use of thespecimen shifiter 3 of the specimen chamber of the electron microscope.The specimen cartridge 11 holding the specimen is then inserted. Thecartridge 11 is rotated by means of the worm drive 9 to make anyoptionally desired orientation of the specimen in parallel to or in theplane of the tilting axis RR. Then any optional portion of the specimenone may desire to inspect is shifted to coincide with the point wherethe three axes meet. Finally, the specimen is tilted at any desiredangle. These adjustments are accomplished by means of the variouscomponents of the present invention employed in the manner describedabove. Since any specific orientation at any portion of the specimen canbe studied with the present device, a continuously successfulthree-dimensional observation of the specimen can be made.

It is to be understood that the term cartridge as it is used in thepresent specification and claims is inclusive of any suitable receptaclethat may be employed in the .manner described. For example, the termtiltable cartridge includes a funnel-shaped member such as shown at 6 inthe accompanying drawing or any member that is suitable for such use.The term specimen cartridge encompasses in addition to member 11 of thedrawings, any other suitable container or receptacle that will serve thepurpose of holding specimens for electron microscopy.

We claim:

-1. A specimen holding device for an electron beam apparatus having anoptical axis comprising:

(A) a stage having (1) an opening through which electron beams passalong said optical axis, and

(2) portions extending downwardly from said opening in the direction ofpassage of said beams through the opening,

(B) an elongated hollow cantridge through which electron beams pass (1)extending through said opening and downwardly extending portions of thestage, and (2) having pivots adjacent its lower end for mounting saidcartridge on said downwardly extending portions of the stage for tiltingabout an axis transverse to said optical axis,

(C) a first mounting plate, 7 p I (l) seated on the upper end of thecartridge, I

(2) rotatable on the cartridge about a central axis parallel to theoptical axis, and

(3) having a central opening through which electron beams pass,

(D) a second mounting plate ('1) seated on said first mounting plate,

(2) having a central opening in line with the central opening in thefirst mounting plate through which electron beams pass,

(3) movable on said first plate transversely to the optical axis;

(E) an elongated hollow specimen holder,

(1) mounted in the opening in said second mounting plate and extendingdownwardly through said hollow cartridge, and

(2) having means for mounting a specimen in the plane of the tiltingaxis of the cartridge,

(F) adjustable means for rotating said first mounting plate,

(G) adjustable means bearing against a portion of the cartridge outsidethe plane of the pivot axis for tilting the cartridge about said tiltingaxis, and

(H) two adjustable mechanisms for moving the second mounting platetransversely of the first mounting plate, said adjustable mechanismsmoving said second mounting plate in directions at right angles to eachother.

2. A specimen holding device as described in claim 1 in which the meansfor moving the second mounting plate transversely of the first mountingplate comprises,

(A) first and second crawl gears surrounding said second mounting plateand supported for rotation about said second mounting plate,

(B) first and second pinion gears (1) meshing respectively with saidfirst and second crawl gears,

(2) spaced approximately from each other about said first mountingplate, and

(3) each having an internally threaded opening extending radially ofsaid first mounting plate,

(C) first and second threaded bolts,

(1) threaded respectively in the threaded openings of said first andsecond pinions,

(2) restrained against rotations so that upon rotation of said pinionsthey will move towards and away from said second mounting plate,

(3) the ends of said bolts nearest the second niounting plate engagingthe second mounting p ate,

(D) a spring tending to resiliently hold the second mounting plateagainst the ends of the bolts which engage the second mounting platewhereby rotation of the pinions moves the second mounting plate, and

(E) means for adjustably rotating said crawl gears to rotate saidpinions.

3. In electron beam apparatus having an optical axis and a holder for aspecimen, the improvement comprising means for shifting the holdertransversely of the optical axis, said shifting means comprising,

(A) a mount for said holder,

(B) first and second crawl gears surrounding said mount and supportedfor rotation about said mount,

(C) first and second pinion gears (1) meshing respectively with saidfirst and second crawl gears,

(2) spaced approximately 90 from each other about said mount, and

(3) each having an internally threaded opening extending radially ofsaid mount,

(D) first and second threaded bolts,

(1) threaded respectively in the threaded openings of said first andsecond pinions,

7 8 (2) and restrained against rotation so that upon References Cited bythe Examiner rotation of said pinions they will move towards UNITEDSTATES PATENTS and away from said mount, (3) the ends of said boltsnearest the mount en- 214181903 4/1947 Runge 250-495 gaging the mount, 52,423,158 7/1947 Runge et al. 25049.5 (E) a spring tending toresiliently hold the mount 2,499,019 2/1950 Dofnfeld 250495 against theends of the bolts which engage the mount 2,713,125 7/1955 Gelsler et250-515 whereby rotation of the pinions moves the mount 2,798,957 7/1957Holden at 250 51-5 transversely of the optical axis, and (F) means foradjustably rotating said crawl gears to 10 RALPH Puma? Examiner rotatesaid pinions. FREDERICK M. STRADER, Examiner.

1. A SPECIMEN HOLDING DEVICE FOR AN ELECTRON BEAM APPARATUS HAVING ANOPTICAL COMPRISING: (A) A STAGE HAVING (1) AN OPENING THROUGH WHICHELECTRON BEAMS PASS ALONG SAID OPTICAL AXIS, AND (2) PORTIONS EXTENDINGDOWNWARDLY FROM SAID OPENING IN THE DIRECTION OF PASSAGE OF SAID BEAMSTHROUGH THE OPENING, (B) AN ELONGATED HOLLOW CARTRIDGE THROUGH WHICHELECTRON BEAMS PASS (1) EXTENDING THROUGH SAID OPENING AND DOWNWARDLYEXTENDING PORTIONS OF THE STAGE, AND (2) HAVING PIVOT ADJACENT ITS LOWEREND FOR MOUNTING SAID CARTRIDGE ON SAID DOWNWARDLY EXTENDING PORTIONS OFTHE STAGE FOR TILTING ABOUT AN AXIS TRANSVERSE TO SAID OPTICAL AXIS, (C)A FIRST MOUNTING PLATE, (1) SEATED ON THE UPPER END OF THE CARTRIDGE,(2) ROTATBLE ON THE CARTRIDGE ABOUT A CENTRAL AXIS PARALLEL TO THEOPTICAL AXIS, AND (3) HAVING A CENTRAL OPENING THROUGH WHICH ELECTRONBEAMS PASS, (D) A SECOND MOUNTING PLATE (1) SEAT ON SAID FIRST MOUNTINGPLATE,